<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Waiting</title>

</head>
<body>
    <button id="B-load" class="load" onclick="load()" >点击加载</button>

<script type="text/javascript">
    var loading = document.getElementById("B-load");
    function load() {
        loading.innerText = "<image src='loading.gif' />";
        loading.disabled = true;

        setTimeout(function () {
            loading.innerText = "加载完成！";
            loading.disabled = false;
        },3000);
    }

</script>
</body>
</html>